Staff of Compleation's third ability by tapping it and paying three life, causing you to put four +1/+1 counters on
Cryptic Trilobite and
Spike Feeder.
Activate
Spike Feeder's second ability twice by removing two +1/+1 counters from it, causing you to gain four life.
Activate
Cryptic Trilobite's first ability three times by removing three +1/+1 counters from it, adding six ({C} magic symbol) that can only be spent to activate abilitieis.
Activate
Staff of Compleation's last ability by paying ({5} magic symbol) , untapping it.
Repeat.
Once you have infinite mana and life, you may activate
Staff of Compleation's other abilities.
Results
Infinite +1/+1 counters on
Cryptic Trilobite and
Spike Feeder.
Infinite card draw.
Infinite colored mana.
Infinite colorless mana that can only be spent to activate abilities.